suggestions for SATA RAID cards

Pete French petefrench at ticketswitch.com
Wed Oct 4 07:49:52 PDT 2006


> I had similar issues as you say with read being much slower than write
> using a highpoint controller the fix was to change the default block
> size of the array to the min the controller supported.

Does anyone have a good feel for a blocksize to use on RAID 1 under
FreeBSD ? I know for a system serving pparallel requests the usual advice
is to have it as large as possible to try and get a single file onto
a single drive, so two in parallel read from a drive each - but for large
files and a single read, do you want to make it somewhat smaller to exploit
parallelism between the drives for a single request ? I have a pair of
drives running as RAID 1 and it is fairly obvious that for a large read it
is alternating between then, rather than reading from both in parallel.
The stripe size there is 64k, what are other people using ?

-pete.


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